Phenylalanine is an essential amino acid, participating in the protein structure, it is a precursor to the synthesis of many secondary metabolites. Secondary compounds play key and important roles in the plant and human health. The importance of phenylalanine and secondary metabolites derived from it and the direct relationship of these compounds with the nutrient-rich, have led to the attention being paid to the gene family of arogenat dehydratase ( adt ), which forms the last step in the synthesis of phenylalanine. Despite the great potential of lentils to increase nutritional value, especially as phenylalanine, so far no studies have been done to identify the arsenate dehydrogenase gene in this plant. In this study, four isoforms of arogenate dehydrate in lentils were detected. for this perpose, initially, the sequence of different isoforms of arogenate dehydrate gene was alighmented against gene bank and based on the conserved regions, specific primers were designed and amplified in lentil. Additionally, primers of the adt1 isoform amplified fragments of approximately 586 nucleotide pairs, adt2 about 367, adt3 about 598 and adt6 about 595 nucleotide pairs. The alighment of sequences with similar sequences in the gene bank database showed a high similarity and therefore the accuracy of sequences was confirmed. Similar regions were observed in all of the detected isoforms in lentils and other plants. These regions are related to the active site of the enzyme in relation to the conversion of sulfate to phenylalanine, as well as the position of phenylalanine binding to the regulation of the dehydratase enzyme. The adt2 isoform found in lentils and in other plants was very similar to the other isoforms, which is justified by the protection and homogenization of this isoform and its key role in providing a consistent need for phenylalanine. The phylogenetic tree resembles the four isoforms of adt in three distinct groups, while the adt3 and adt6 have the most similar isoform and are divergent. These results were consistent with the results of the phylogenetic tree of Arabidopsis. Keywords : Food Value, Lentil, Phenylalanine, Arogenat dehydratase